1. Field of the Invention
The present invention relates to an image processing device, an image processing method and an image processing program, and more particularly to an image processing device and image processing method for processing image data in order to display an image at a reflecting-type display medium which is capable of color display.
2. Description of the Related Art
Heretofore, image display mediums which have excellent display image retention characteristics and are repeatedly rewritable have been proposed, such as, for example, twisting ball displays (display by rotation of particles which are each coated half-and-half with two colors), magnetophoresis-type display mediums, thermal-rewritable display mediums, liquid crystal displays with memory characteristics, and so forth.
However, these display mediums have problems in not being able to display white colors as of paper and in having low image contrast.
Accordingly, as an image display medium for overcoming the problems described above, the technology described in, for example, Japanese Patent Application Laid-Open (JP-A) No. 2002-277906 has been proposed. For the technology described in JP-A No. 2002-277906, it is proposed that an electrophoretic display element contains a dispersion medium including liquid crystals and contains electrophoretic particles formed of titania or the like, which are dispersed in the dispersion medium. In this electrophoretic display element, the dispersion medium that is employed contains a first colorant, which is formed of a dichroic colorant featuring a high dichroism ratio, and a second colorant, which is formed of a dichroic colorant featuring a low dichroism ratio and/or two colorants formed of isotropic colorants. The first colorant and the second colorant are set with a mutually complementary color relationship. Hence, white, black and the other color displays are realized with a single capsule.
However, in an image display medium with a reflection-type juxtaposed-color structure, in which a single pixel is structured by three or more sub-pixels, when R (red), G (green) and B (blue) are displayed for displaying white, reflectivity is limited to 33% relative to an ideal white. Moreover, there is a problem in that it is necessary to establish white balance between R, G and B, so a degree of freedom of design of the colors R, G and B is reduced.
Moreover, with the technology described in JP-A No. 2002-277906, three-color display with individual dots is proposed. However, there is no discussion of data preparation of juxtaposed colors and there is no discussion of ideas such as substituting RGB with WWK {white, white, black} or the like, and there is still room for improvement in reproduction of white.